Dr David Humphreys

BACKGROUND: Ridesharing services (eg, Uber, Lyft) have facilitated over 11 billion trips worldwide since operations began in 2010, but the impacts of ridesharing on motor vehicle injury crashes are largely unknown. - METHODS: This spatial ecological case-cross over used highly spatially and temporally resolved trip-level rideshare data and incident-level injury crash data for New York City (NYC) for 2017 and 2018. The space-time units of analysis were NYC taxi zone polygons partitioned into hours. For each taxi zone-hour we calculated counts of rideshare trip origins and rideshare trip destinations. Case units were taxi zone-hours in which any motor vehicle injury crash occurred, and matched control units were the same taxi zone from 1 week before (-168 hours) and 1 week after (+168 hours) the case unit. Conditional logistic regression models estimated the odds of observing a crash (separated into all injury crashes, motorist injury crashes, pedestrian injury crashes, cyclist injury crashes) relative to rideshare trip counts. Models controlled for taxi trips and other theoretically relevant covariates (eg, precipitation, holidays). RESULTS: Each additional 100 rideshare trips originating within a taxi zone-hour was associated with 4.6% increased odds of observing any injury crash compared with the control taxi zone-hours (OR=1.046; 95% CI 1.032 to 1.060). Associations were detected for motorist injury and pedestrian injury crashes, but not cyclist injury crashes. Findings were substantively similar for analyses conducted using trip destinations as the exposure of interest. CONCLUSIONS: Ridesharing contributes to increased injury burden due to motor vehicle crashes, particularly for motorist and pedestrian injury crashes at trip nodes.

BACKGROUND:Intimate partner violence is the most common form of violence perpetrated against women. To our knowledge, the effect of neighborhood disadvantage on intimate partner violence against women has never been investigated prospectively outside the United States. METHODS:We used data from the Avon Longitudinal Study of Parents and Children in the United Kingdom, which followed our target sample, 7,219 women, from birth and their mothers (from pregnancy). At age 21, 2,128 participants self-reported the frequency of experiencing physical, psychological, or sexual intimate partner violence since age 18. Participants' exposure to neighborhood-level deprivation and family-level socioeconomic characteristics (e.g., income) were measured at 10 time points from baseline (gestation) until children were 18 years old. We estimated the effect of cumulative exposure to greater neighborhood-level deprivation on the risk of experiencing intimate partner violence using marginal structural models with stabilized inverse probability weights, accounting for time-varying confounding by socioeconomic indicators and sample attrition. RESULTS:A one-unit increase in cumulative exposure to more severe neighborhood deprivation was associated with a 62% increase in participants' frequency of experiencing intimate partner violence (95% confidence interval 11%, 237%) and 36% increase in their risk of experiencing any intimate partner violence (95% confidence interval 1%, 85%). CONCLUSIONS:In our study, cumulative exposure to greater neighborhood deprivation over the first 18 years of life was associated with women's increased risk of experiencing intimate partner violence in early adulthood. Future studies should test this association across contexts, including underlying mechanisms, and evaluate preventive strategies that target structural disparities.

BACKGROUND:Child maltreatment is associated with an increased risk of antisocial behaviour; however, whether this risk persists and remains stable across the life-course is undetermined. OBJECTIVE:To examine associations between chid maltreatment and antisocial behaviour across the life-course. PARTICIPANTS AND SETTING:The study used 50 years of longitudinal data from the 1958 British birth cohort (n = 8088) measuring child neglect (prospectively) and abuse (retrospectively) and antisocial behaviour from childhood-to-adulthood. METHODS:Latent growth curve models analysed the longitudinal course of antisocial behaviour across childhood (7-16years) and adulthood (23-50years) as a function of child maltreatment. We used directed acyclic graphs to identify, and adjust for, potential confounders (biological, family, social). RESULTS:Child maltreatment was associated with higher levels of antisocial behaviour at all seven timepoints across the life-course (7-50years). Antisocial behaviour was elevated during childhood and adulthood in individuals who were maltreated, independently of confounding factors. Individuals who experienced multiple types of maltreatment were at the greatest risk of antisocial behaviour. Each additional maltreatment type was associated with an increased risk during both childhood (B = 0.173; SE = 0.024; p < .001) and adulthood (B = 0.137; SE = 0.014; p < .001). There was limited evidence that child maltreatment was associated with within-person rates of change, indicating that the increased risk of antisocial behaviour did not change over time. CONCLUSIONS:Child maltreatment is associated with an increased risk of antisocial behaviour, with a persistent and stable association remaining up to age 50. Our results highlight the burden of child maltreatment and the importance of providing long-term support for individuals who experience child maltreatment.